Resiliently biased pilot axle arrangement

ABSTRACT

A railway vehicle truck having a frame provided with a plurality of spaced apart wheel supporting driven axles and a resiliently biased front pilot axle assembly. The front idle axle assembly comprises a pilot axle housing for supporting a pilot axle having a wheel at each end thereof. The pilot axle housing is connected to the frame by precompressed elastomer blocks interposed between the frame and the pilot axle housing. The precompressed elastomer blocks permit smooth guided movement of the pilot axle housing in an arcuate horizontal plane and in the vertical plane.

O United States Patent 11 1 in] 3,724,393

Parker et a]. 51 Apr. 3, 1973 54 RESILIENTLY BIASED PILOT AXLE 3,115,100l2/l963 Janeway ..105/174 ARRANGEMENT 2,349,568 5/1944 Travilla, Jr...105/l74 [76] Inventors: 2 gr g F t 730 Saint Primary Examiner-GeraldM. Forlenza u m T amt aurem Assistant Examiner-Howard Beltran bec; F.Thomas Mclnerney, III, 190 Atmmey Alan Swabey de Normandie Saint Bruno,QuebC, both of Canada 57 ABSTRACT [22] Filed: 1971 A railway vehicletruck having a frame provided with [211 App]. No.: 114,656 a pluralityof spaced apart wheel supporting driven axles and a resiliently biasedfront pilot axle assembly. The front idle axle assembly comprises apilot axle 2% 8 housing for supporting a pilot axle having a wheel at d105 8 172 each end thereof. The pilot axle housing is connected 1 o areI to the frame by precompressed elastorner blocks inter- 1 posed betweenthe frame and the pilot axle housing. [56] References C'ted Theprecompressed elastorner blocks permit smooth UNITED STATES PATENTSguided movement of the pilot axle housing in an arcuate horizontal planeand in the vertical plane. 2,994,284 8/1961 Travilla ..l05/l74 227,029-4/1880 Mason ..l05/174 X 13 Claims, 3 Drawing Figures PATENTEDAFR 3 m5INVENTOR John Henry PARKER F. Thomas McINERNEY III A TTORNEY BACKGROUNDOF THE INVENTION a. Field of the Invention This invention relates to apilot axle assembly suspension for a motorized truck for locomotive orthe like powered vehicles.

b. Description of Prior Art Motorized trucks for locomotives or the likepowered vehicles normally comprise a plurality of motorized axles havinga flange wheel at each end thereof, for supporting the vehicle on rails.During operation and more particularly when the vehicle has to followcurved rails, the wheel flanges of the wheels of the front axle aresubjected to considerable wear because of the lateral force applied tothe flange by the curve track section. The force exerted on the flangeis also transmitted to the front axle which is also subjected to some ofthe stress. Further, with a rigid front axle the wheels have a tendencyto climb and jump the rails when entering a curve rail section as thetrailing powered wheels of the locomotive tend to push the vehiclestraight ahead as these further wheels have not yet entered the curverail section.

These problems have been greatly reduced by the provision of a frontpivoted pilot axle which will assist the trailing powered wheels tofollow curve rail sections. However, these further wheels are stillsubjected to a certain amount of force or stress between the flange ofits wheels and the outside rail of the curved SUMMARY OF INVENTION It isan object of the present invention to provide a pilot wheel suspensionfor a motorized truck. for locomotives or the like poweredvehicles whichsubstantially reduces the above-mentioned disadvantages.

Accordingly, from one aspect, the present invention provides a railwayvehicle truck having a frame provided with a plurality of spaced apartwheel supporting driven axles and a front pilot axle assembly. The frontpilot axle assembly is provided with means for supporting a pair ofwheels and including precompressed resilient means interposed betweenthe pair of wheels and the truck frame. The precompressed resilientmeans permits smooth guided movement between the pair of wheels and theframe in a plurality of planes.

BRIEF DESCRIPTION OF DRAWINGS The invention is illustrated, by way ofexample, with reference to the embodiment shown by the accompanyingdrawings in which:

FIG. 1 is a top plan view, partly fragmented, of a truck frame assembly;

FIG. 2 is a side view, partly fragmented, of the pilot idle wheelassembly; and

FIG. 3 is a side view of an elastomer spring element.

DESCRIPTION OF PREFERRED EMBODIMENTS Referring now to the drawings, andmore specifically to FIG. 1, there is shown, generally at 10, a truckframe assembly for supporting a locomotive or the like vehi cle, notshown. The truck frame assembly 10 comprises a truck frame 11 having aplurality of powered wheels 12 supported in spaced relationshiptherealongAt the front end of the truck frame 1 1 there is provided apilot idle wheel assembly 13 for guidance of the truck frame 11. Theassembly 13 is retained for axial and vertical movement with the frontend 14 of the truck frame 1 1.

With additional reference to FIGS. 2 and 3 of the drawings, it can beseen that the pilot idle wheel assembly comprises a horizontal,substantially elongated, pilot axle housing 15 held transverse to thelongitudinal center line 16 of the truck frame 11. An unpowered axle 18is supported by bearings 19 journaled at each end of the pilot axlehousing 15. A wheel 20 having an inner side flange 21 is secured forrotation at each end of the idle axle 18. The pilot axle housing 15 isheld between a plurality of elastomer elements or elastomer blocks 30a,30b, 30c and 30d. The upper face 22 of the pilot axle housing 15supports one end of a set of compression springs 50, 51 and 52, locatedon the trans verse center of the housing. The other end of the set ofcompression springs 50, 51 and 52 support the front end 14 of the truckframe 11. A vertical limit stop device 17 is secured to the upper face22 of the pilot axle housing 15 and to the truck frame front end 14 tolimit downward displacement of the compression springs 50, 51 and 52which are exerting a downward pressure. Theaxle housing 15 is furtherheld between a plurality of resilient means in the form of elastomerblocks 30 (see FIG. 3) which consists essentially of a plurality of flatintermediate metal plates 40 (hereinshow ten plates) disposed betweenthe end plates 41 and positioned in alternating series with a pluralityof elastomer elements 43. The elastomer elements 43 have flat faces forbonding by such means as vulcanizing between the metal plates 40 and theend plates 41. The elastomer blocks 30 may be of various harness andalso may have perforations therein to modify their elastic or resilientproperties. The elastomer blocks 30 have an indefinite life because oftheir constructions employing substantially nonwearing parts and requireno lubrication. Also, these blocks are resistant to many environmentalelements such as grease, water, frost, etc., and therefore needssubstantially no servicing.

The axle housing 15 is provided with two bearing surfaces 25 and 26disposed in a vertical plane in the front face thereof to receive theabutting surface 31 of the end plate 41 of a respective elastomer block30 herein referred to as the front pair of elastomer blocks 30a and 30b.Each of the elastomer blocks 30a and 30b of the front pair aresymmetrically spaced-apart, one on each side of the central horizontalplane 27 of the idle axle 18 and each centered on the longitudinalcenter line 16 of the truck frame 1 1. Elastomer blocks 30a and 30b areheld in compression between the bearing surfaces 25 and 26, and theinner face 34 of a clamp plate 35. The clamp plate 35 is held rigidlyvertically in the front portion 14 of the truck frame 11 in front of thepilot axle housing 15.

Further bearing faces 28 and 29 are provided on the rear face of theaxle housing 15, one near each end thereof, and are disposed in avertical plane facing angularly inwardly towards the longitudinal centerline 16 so that the central longitudinal axis 32 of the rear pair ofelastomer blocks 30c and 30d, resting thereon, intersect with thelongitudinal center line 16 to provide an idealangular displacement ofthe pilot axle in a freely guided arcuate horizontal plane. The rear'pair of elastomer blocks 30c and 30d are also held in compressionbetween their end plates by respective angularly disposed bearingsurfaces 36 and 37 provided in the front end of the truck frame 11 andbearing surfaces 28 and 29 on the rear face of the pilot axle housing15. Bearing surfaces 36 and 37 lie parallel to bearing surfaces 28 and29.

Mounted between the front end of the truck frame 11 and the pilot axlehousing is a centering device 55. The centering device 55 consists oftwo metallic arms 56 and 57 secured respectively of an inner and outermetallic sleeve (not shown), the sleeves being interconnected by anelastomer core (not shown). in the installed state, the arms 56 and 57are displaced angularly toward each other, thus causing a stress in therubber and thus an outward force at the ends of the arms 56 and 57. Thearms 56 and 57 are held in a spaced together position and equidistantlyon a respective side of the center line 16 by two tongues (not shown)formed integrally with the front end of the truck frame 11. Two furthertongues 58 are located on the rear face 59 of the pilot axle housing 15and positioned symmetrically about the center line 16 and spaced apartto align with the tongues on the truck frame 1 1, and thus with the endsof the arms 56 and 57. it will be recognized by those skilled in the artthat this arrangement constitutes a pre-load at the center position ofthe pilot axle assembly such that a force at the flange 21 will notdisplace the pilot axle assembly until said force exceeds the forcebeing exerted against the tongues on, the truck frame 11 by the arms ofthe centering device. it will be recognized that all of the elasticelements vis. the compression springs, elastomer blocks, and centeringdevice, all contribute to the total restoring force. The propercombination of all rates and pre-load setting of the centering device isfundamental to the design in securing the proper guidance from the pilotaxle assembly. Thus, when the pilot axle housing is axially displaced, arestoring force of the desired magnitude is provided by theaforementioned elastic elements to assist in guiding the frame 11 andthus the motorized axles so that the pilot axle and following motorizedaxles each assume respectively the desired proportion of the requiredcurve negotiating flange force.

in operation, as the pilot idle axle assembly 13 enters a curvate railsection (for purpose of description we will assume that the rail sectioncurves to the left of the front end of the truck frame 11 as shown inFIG. 1) a force is applied to the flange 21 of the right wheel by theoutside right rail (not shown). This force is transmitted to the idleaxle l8 and when said force exceeds the pre-load provided by thecentering device 55, the axle housing 15 is displaced in a guidedarcuate horizontal plane 60 which is predetermined by the disposition ofthe elastomer pads.

The rear elastomer blocks 30c and 30d are positioned with their centralperpendicular axis 32 lying in the same plane as the radius of thearcuate plane 60. The elastomer blocks 30a, 30b, 30c and 30d are furtherprecompressed between their associated bearing surfaces. When the blocks30 are compressed longitudinally they offer a very stiff resistance. Theblocks 30 are sufficiently compressed to shear at the maximum arcuate orvertical displacement.

it is within the ambit of the present invention to provide a singleelastomer block between the front vertical face of the axle housing andthe front clamp plate. However, such elastomer block may be madesubstantially larger. Also, further modifications will be evident tothose skilled in the art without departing from the scope of theinvention as set forth in the appended claims.

We claim:

1. In a railway vehicle truck having a frame provided with a pluralityof spaced apart wheel supporting driven axles and a front pilot axleassembly; said front pilot axle assembly having a pilot axle housing forsupporting a pair of wheels; said assembly including precompressedresilient means located between said housing and said truck frame andfore and aft of said housing; said precompressed resilient meanspermitting predetermined constrained movement of said housing invertical and horizontal planes. I

2. A railway vehicle truck as claimed in claim 1 wherein said elastomerblocks each comprise two metallic end plates having a plurality ofelastomer elements and intermediate metal plates bonded in alternatingseries between said two metallic end plates.

3. In a railway vehicle truck having a frame provided with a pluralityof spaced apart wheel supporting driven axles and a front pilot axleassembly; said front pilot axle assembly comprising a pilot axle housingsupporting a pilot axle having a wheel at each end thereof, saidpilotaxle housing being connected to said frame by precompressedelastomer blocks interposed between said frame and said pilot axlehousing and fore and aft of said housing; said precompressed elastomerblocks permitting predetermined constrained movement of said pilot axlehousing in an arcuate horizontal plane and in the vertical plane.

4. A railway vehicle truck as claimed in claim 3 wherein said elastomerblocks associated with said two inclined bearing surfaces are eachmaintained in precompression between its respective one of said inclinedbearing surface in said axle housing and a further inclined bearingsurface formed integrally in the front of said truck frame, said bearingsurfaces at each end of a respective elastomer block being disposedparallel to each other.

5. A railway vehicle truck as claimed in claim 3 wherein two bearingsurfaces are provided in the front face of said axle housing andpositioned to support a respective elastomer block, each said elastomerblock being symmetrically spaced apart, one on each side of the centralhorizontal plane of said pilot axle and each centered on thelongitudinal center line of said truck frame.

6. A railway vehicle truck as claimed in claim 3 2 block disposedsymmetrically on the truck longitudinal center line, and two inclinedbearing surfaces respectively disposed in a vertical plane andsymmetrically spaced apart on a respective side of the trucklongitudinal center line, in the rear face of said pilot axle housing,each said inclined bearing surface adapted to receive in bearing contacttherewith one end of a respective elastomer block.

7. A railway vehicle truck as claimed in claim 6 wherein said twoinclined bearing surfaces are disposed angularly inwardly towards saidtruck longitudinal center line; the central longitudinal axis of eachsaid elastomer spring element associated with said two bearing surfaces,intersecting with said center line inwardly of said truck frame.

8. A railway vehicle truck as claimed in claim 6 wherein said at leastone elastomer block is maintained in precompression between said bearingsurface in the front face of said axle housing and the inner face of aclamp plate held rigidly in a vertical plane in the front of said truckframe, said bearing surface and clamp plate inner face being disposedparallel to each other.

9. A railway vehicle truck as claimed in claim 6 wherein saidprecompressed elastomer blocks will shear when said pilot axle housingis displaced in a vertical plane or in an arcuate horizontal plane andretain a compression.

10. A railway vehicle truck as claimed in claim 6 wherein a plurality ofprecompressed helical springs are positioned above said pilot axlehousing and maintained in compression with the top surface thereof andsaid truck frame by means of a limit stop device secured between saidtop surface and said truck frame.

11. A railway vehicle truck as claimed in claim 6 wherein a centeringdevice is secured between said truck frame and said pilot axle housing,said centering device being adapted to exert a restoring force to saidpilot axle housing when displaced axially to thereby restore said idleaxle wheels in the same plane as said wheels secured to said drivenaxles.

12. A railway vehicle truck as claimed in claim 11 wherein a totalrestoring force is provided by the combination of the force exerted bysaid restoring device, the shear displacement of the ends of thevertical springs mounted on top of said axle housing and the forcecaused by the shear displacement of the elastomer blocks.

13. A railway vehicle truck as claimed in claim 11 wherein saidcentering device is arranged in a manner that the pilot axle is heldcentered until a preselected flange force is exceeded.

1. In a railway vehicle truck having a frame provided with a pluralityof spaced apart wheel supporting driven axles and a front pilot axleassembly; said front pilot axle assembly having a pilot axle housing forsupporting a pair of wheels; said assembly including precompressedresilient means located between said housing and said truck frame andfore and aft of said housing; said precompressed resilient meanspermitting predetermined constrained movement of said housing invertical and horizontal planes.
 2. A railway vehicle truck as claimed inclaim 1 wherein said elastomer blocks each comprise two metallic endplates having a plurality of elastomer elements and intermediate metalplates bonded in alternating series between said two metallic endplates.
 3. In a railway vehicle truck having a frame provided with aplurality of spaced apart wheel supporting driven axles and a frontpilot axle assembly; said front pilot axle assembly comprising a pilotaxle housing supporting a pilot axle having a wheel at each end thereof,said pilot axle housing being connected to said frame by precompressedelastomer blocks interposed between said frame and said pilot axlehousing and fore and aft of said housing; said precompressed elastomerblocks permitting predetermined constrained movement of said pilot axlehousing in an arcuate horizontal plane and in the vertical plane.
 4. Arailway vehicle truck as claimed in claim 3 wherein said elastomerblocks associated with said two inclined bearing surfaces are eachmaintained in precompression between its respective one of said inclinedbearing surface in said axle housing and a further inclined bearingsurface formed integrally in the front of said truck frame, said bearingsurfaces at each end of a respective elastomer block being disposedparallel to each other.
 5. A railway vehicle truck as claimed in claim 3wherein two bearing surfaces are provided in the front face of said axlehousing and positioned to support a respective elastomer block, eachsaid elastomer block being symmetrically spaced apart, one on each sideof the central horizontal plane of said pilot axle and each centered onthe longitudinal center line of said truck frame.
 6. A railway vehicletruck as claimed in claim 3 wherein said pilot axle housing is providedwith at least one bearing surface in the front face thereof extending ina vertical plane and adapted to receive in bearing contact therewith oneend of at least one elastomer block disposed symmetrically on the trucklongitudinal center line, and two inclined bearing surfaces respectivelydisposed in a vertical plane and symmetrically spaced apart on arespective side of the truck longitudinal center line, in the rear faceof said pilot axle housing, each said inclined bearing surface adaptedto receive in bearing contact therewith one end of a respectiveelastomer block.
 7. A railway vehicle truck as claimed in claim 6wherein said two inclined bearing surfaces are disposed angularlyinwardly towards said truck longitudinal center line; the centrallongitudinal axis of each said elastomer spring element associated withsaid two bearing surfaces, intersecting with said center line inwardlyof said truck frame.
 8. A railway vehicle truck as claimed in claim 6wherein said at least one elastomer block is maintained inprecompression between said bearing surface in the front face of saidaxle housing and the inner face of a clamp plate held rigidly in avertical plane in the front of said truck frame, said bearing surfaceand clamp plate inner face being disposed parallel to each other.
 9. Arailway vehicle truck as claimed in claim 6 wherein said precompressedelastomer blocks will shear when said pilot axle housing is displaced ina vertical plane or in an arcuate horizontal plane and retain acompression.
 10. A railway vehicle truck as claimed in claim 6 wherein aplurality of precompressed helical springs are positioned above saidpilot axle housing and maintained in compression with the top surfAcethereof and said truck frame by means of a limit stop device securedbetween said top surface and said truck frame.
 11. A railway vehicletruck as claimed in claim 6 wherein a centering device is securedbetween said truck frame and said pilot axle housing, said centeringdevice being adapted to exert a restoring force to said pilot axlehousing when displaced axially to thereby restore said idle axle wheelsin the same plane as said wheels secured to said driven axles.
 12. Arailway vehicle truck as claimed in claim 11 wherein a total restoringforce is provided by the combination of the force exerted by saidrestoring device, the shear displacement of the ends of the verticalsprings mounted on top of said axle housing and the force caused by theshear displacement of the elastomer blocks.
 13. A railway vehicle truckas claimed in claim 11 wherein said centering device is arranged in amanner that the pilot axle is held centered until a preselected flangeforce is exceeded.